1. Technical Field
The present invention relates to bending restrictors and bending strain restrictors designed for cables, pipes and other elongated articles such as umbilicals, which are installed in connection with offshore constructions. In the following the invention will be described in connection wish installation of a cable from a cable ship.
2. Description of the Prior Art
Offshore cables are designed to withstand strains caused by bending under tension such as passing the cable over a bow wheel of the ship. The cables are also to a certain extent designed to withstand repeated flexing after installation and during normal operation. In most cases at least one end of the cable is provided with a termination head for simplifying interconnection of the cable with an offshore construction such as a template arranged on the sea bed. In such cases a critical installation phase is to bring the cable with the termination head safely from the cable ship down to the template. Such termination heads may weigh 5 tons and more.
Bending strain restrictors are normally designed such that the combined stiffness of the elongated article itself and the restrictor is gradually reduced along the article from the position where the restrictor is clamped to installation head.
The main purpose of a bending restrictor (BR) is to limit the bending diameter of a cable to a minimum value, whereas the main purpose of a bending strain restrictor (BSR) is to restrict the strain in the cable when it is bent.